Multiple-contact electric switch



H. J. NORBALLE AND 1. L. LAWSON.

MULTIPLE CONTACT ELECTRIC SWITCH.

APPLICATION FILED MAB.10;1920.

Patented Jan. 31, 1922.

2 SHEETS-SHEET I.

avail 1| H. J. NOR'BALLE AND 1. L. LAWSON.

MULTIPLE CONTACT ELECTRIC SWITCH.

APPLICATION FILED MAR. I0, 1920.

Patented Jan. 31, 1922.

2 SHEETSSHEET 2.

UNITED." STATES PATENT OFFICE.

HANS JACOB NORBALLE AND JAMES LIDDLE LAWSON, or HERTFORDSHIRE, ENGLAND.

' mun'rrrnnoou'rnor ELECTRIC SWITCH.

Specification of Letters Patent. 7 Patented J an. 31, 1922.

h ucatidn filed March 10, 1920. Serial No. 364,664.

(GRANTED UNDER THE I R OVISION S 01* THE ACT OF MARCH 3, 1921, 41 STAT.L, 1313.)

T 0 all-whom it may concern:

Be 1t known that we,"HANs JACOB NoR- BALLE and JAMES LIDDLE Lawson,subjects of the King of England, and both residing at Hertfordshire,England have invented certain new and useful Improvements inMultiple-Contact Electric Switches, (for which we have filed anapplication in England No. 17988, filed the 13th of ()ctober, 1913,application accepted LOctober 13th, 1914, patent sealed December 311914,) of

which the follow'ing is a specification.

According to the present invention in a multiple contact switch having arow of contact-pleces and a contact-bar therefor,

each lcontact-piece is provided with a flat structionone end-is pivotedeither to a par-t guided in a'straight line path or to a swinging linkand the other end is pivotally connected to a swinging link in such amanner as to swing in a "path 'whose direction is transverse to that ofthe' i novement of the first said end. Theconnection' between thecontact-bar and themeans whereby one of its ends is guided more or "lessin the direction of the line'of'the row of contact-pieces is preferablya pin-and-inclined-slot' connection for the purpose hereinafter referredto. Each contact-piece is preferably so resiliently supported new becapable both of a pivotal movement and of a bodily displacement toenable it to adjust itself to the movements of the" co-operatingcontact-bar.

The'object of this construction is to give the bar such a movement that,at the moment of contact with e'ach contact-piece, the con tact edge ofthe bar at that part is parallel with the fiat'face of'the piece, andmoves so as to touch the piece over the whole contact areasimultaneously, andfurther, having made such contact, to produce asubsequent rubbing movement between the surfaces. L a

The invention consists in the construction,

arrangement and combination of parts described hereinafter and pointedout in the claims.

One embodiment of the invention and a modification thereof arediagrammatically represented by way of example in the accompanyingdrawings, in which Figure '1' shows in elevation one constructionaccording to the invention comprising a contact-bar and contact-piecesarranged for a motor-starter panel, and I Figure 2 is a perspective viewof a contactpiece and its support;

Figure 3 is a view similar to Figure 1 of a modification. r

Like reference letters designate like throughout the several views.

As seen in Figure l, E is a contact-bar for use in an automaticmotor-starter. The con tact-bar is provided with a contact-strip Eforming the contact-face, and is pivoted at its lower end at E to abarB, from which two downwardly-directed roos B B extend through guides C Cmounted on a panel A to give straight line motion to the bar B. Anyconvenient mechanism may be used for moving the bar 13 in a straightline. The contact-bar is thus carried by the bar Band moves with it, butis guided as'to its upper. end by pivotal engagement with a swinginglinkL.

The one end ofthis link L is pivoted at L in the slot E in the bar E,and the other end is pivoted to the panel A at L a buffer stop beingprovided at L A numberof contactpieces M are arranged in a row in whicheach contact-piece is slightly set back laterally relatively to itsfellowbeneath it. Each contact-piece has a contact-face F, and has thatface so directed that .it will be parallel to the face of the strip E atthe instant of contact. The way which this position is arrived at isshown in Figure 1, where the numerals l to 8 upon the lower end of thecontact-bar E indicate successive positions of the pivotal centre E anddotted lines numbered 1 to 8 show the corresponding positions of thecontact-face of the strip E corresponding successive positions of thepivotal centres L are shown and numbered 1 to S at the upper end of thebar.

Each contactpiece is constructed as shown in Figure 2; where M is acarbon block mounted upon a conducting pin M The upper end of this pinenters an elongated parts 35 tact is thus made simultaneouslyover thewhole area of a face F. lVhen contact has been established in this waythe continued movement ofthe bar E gives rubbing action uponthe block,andthe latter moreover both, j yields bodily and receives a small notionof hole M in the-carbon bloclrof such a size as to give not only pivotalmovement, but suiiicient play to permit a small bodily'movement oftheblock M with relation to the pin M Towards its lower end the pincarries a metal block l 7 on which issupported direction aboutthe pinlvlVA split sleeve 7 electrical connections to it.

M upon-the pin -M -is connected by a flexible conductor W to a. splitpin h 5 held frictionally in a hole in the block M. The screwthread a. Mis toreceive nuts,'rnot shown, for securing it in pos1t1on, and forclamplng In operation, as the bar B is raised from thezposition shown inFigure 1, "itcauses thellower end'of the bar E, to follow a straightline path, while the upper end swings aboutthe centre L The slot Eperinits, however, a certain amount of lost mo,- tion, which when theparts are soleno1d-op- 'erated is advantageous." lvhen the pin L isstruck by the bottom end of the slot E r the upper end of thecontact-bar E follows a circular path and thewhole barsuccessivelytakesup positions in'which itscon tact-face occupies the-"positions shown indotted lines numbered 1 to 8. --The facesvF, however, of the blocks -Mare so setthat as each encounteredby the strip E the/contact-face of thelatter and the contact-face of the block are parallel to one another,con-

' rotation about the end M? of its pin.

a Fixed metal contactpieces N, N ,'ancl N I may be provided, if desired,taco-operate with the rear or under facevof the contactbar, 'thatcis t0sayfthe face iof the contacts strip E 77 turned towards the panel, topro- 1 vide a short-circuitfpath of really low resistance to the mainresistance from which tappings are taken to the blocks' M.

An alternative construction is shownin Figure 3 which differs. from thatshown in Figure v1, in that the lowerend of a contact bar Ecorresponding to the bar E does not receive a straight ilinemotion. Thisbar E is pivotally connected by apin l3 movable in a slot B to a bar Bwhich is itself pivoted atB' on the panel A and is the member bywhich'the bar E isoperated. The means shown for swingingthe barcompriseva 11111: B that 1s connected at one endto the core of asolenoid and carrles at its other end a pin movable in a slot 13 in thebar B At its upper end the pivotal connection of'the liar E with thelink L is by means of a plain pivotL instead of a pin-and-slotconnectio'n L E as in igure l; The sl ot '13 at the lower end has-itsdirection inclined both to the general direction ofthe thrust of thecontact-pieces M and to the principal direction of movement of the bar EThe purpose ofthis pin-and-slot arrangement is to avoid binding actionupon the bar B at its pivot B7 asa result of the cornbined thrust of thecontact-pieces -M. As the bar B travels upwards the pin Btabutsagainstthe lower end of'the; slot B), but so'soon as the bar B begins to fall,pressure from the blocks M is eased the slotB It is preferred,'

There aidash-pot is em owing to the direction of 'ployed, to provide oneas seen at'G, but 'so constructed as tohavea release port which comesinto action when the bar'is just ap V proaching the topof its stroke, sothat this portion of'its travel, a very smallportion, is

executed unchecked by any dash-pot action 7 and therefore 'by a'movementsomewhat in 1 the naturejof a jerk; this facilitates the upward movementinspite of theaccumulated pressure of the 'contact pieces 7M; Thisarrangement'of dash-pot may be applied either Figure 3 or; to;

1. Inan electric switch, the combination of a. row ,of spring-controlledcontact-pieces having ,eaeha flat contact-face, a contact-f bar having acontact-faceextending length wise along itself, and-means for guidingsaid contactbar so that one endthereofh-as a path e itending in thedirection the l'ine' of said row'ofcontact-pieces, the other endithereofhas; a path whose direction is transverse to that of the first :end, andits contact facef is broughtinto contact in suc cession with thecontac't-facesof the contact- 7 i pieces, and means supporting saidcontact 7 pieces so that their contact-faces when free.

are each directed to be substantially, parallel with the direction whichthe co-operating portion of the contact-face of the bar has at 7' themoment of contact therewith. p 2. In an electric switclnthe combinationhaving each aflat contactface, a contact-bar having acontact-faceextending lengthwise along itself, and means for guidingsaid con-,

tact-bar'so that one end thereof follows a path extending intheldirection of the line of said row of contact-pieces, the other endthereof swings about a pivot along a path whose direction is transverseto that of the first end,rand its contactface is brought into contact'with the contact-faces of the contact-pieces successively, and meanssupportingsaid contact-pieces so that their contact-f of a row ofspring-controlled contactgpieces the co-operating portion ofthe-contact-face of: the :bar has" atthe moment 1 of :contact therewith,

3. In an electric switch, the combination of a .row of spring-controlledcontact-pieces having each a flat contact-face, a contact-bar having acontactfaceiextending lengthwise along itself, and guiding means forsaid bar comprising a' guide member having one end that is pivoted toone end of saidba-r and is movable in a pathiextending'in' the directionof the line of said row of contact-pieces, and a link that is fixedlypivoted at one end and has its other end pivotally connected to theother end of said bar and movable along a path whose direction istransverse to that of the former end, said guiding means being v soarranged that the contact-face of the contact-bar is brought intocontactin succession with the contact-faces of the said contactpieces,and means supporting said contactpieces so that their contact-faces whenfree are each directed to be substantially parallel with the directionwhich the co-operating portion of the contact-face of the bar has at themoment of contact therewith.

4. In'an electric switch, the combination of a row ofcontact-pieceshaving each a flat contact-face, a contact-bar having a contactfaceextending lengthwise along itself, guiding means for said bar comprisinga guide member having one end that is pivotally connected by apin-and-slot connection to one end of said bar and is movable in a pathextending in the direction of the line of said I contact-pieces, and alink that is fixedly pivoted at one end and has its other end pivotallyconnected to the other end of said bar and movable along a path whosedirection is transverse to that of the former end, said guiding meansbeing so arranged that the contact-face of the contact-bar issuccessively brought into contact with the contactfaces of the saidcontact-pieces, and means yieldingly supporting said contact-pieces insuch manner that their contact-faces when free are each directed to besubstantially parallel with the direction which the co-opcrating portionofthe contact-face of the bar has at the moment of contact therewith.

5. In an electric switch, the combination of a row of contact-pieceshaving each afiat I contact-face, a contact-bar having a contactfaceextending along itself, means for guiding said bar comprising a. guidemember that is mounted to swing about a fixed pivot and has one end thatis pivoted to one end of said bar and is movable in a path extending inthe direction of the line of said row of contransverse to that of theformer end, said guiding means being so arranged that the contact-faceof the; contact-bar is brought into contact.- with the contact-faces ofthe contat-pieces insuccession, and means supportingthe saidcontact-pieces in such manner that their contact-faces when free areeach directed to be substantially parallel with the direction which theco-operating portion Ofxt'l lQ ccntact face of the bar has at the momentof contact therewith.

-"6.'In. an electric switch, the combination ofarow of contact-pieceshaving each a flat contact-face,:a contact-bar having a contactfaceextending along itself, guiding means for said bar comprising a guidemember having one end that is pivotally connected by a pin-and-slotconnection to one end of said bar and is movable in a path extending inthe direction of the line of said contactpieces, and a link that isfixedly pivoted at one end and has its other end pivotally connected tothe other end of said bar and movable along a path whose direction istransverse to that of the former end, the slot of the pin-and-slotconnection being directed transversely both to the general direction ofthe row of contact-pieces and to a direction at right-angles thereto,said guiding means being so arranged that the contact-face of thecontact-bar is successively brought into contact with the contact-facesof the said contact-pieces, and means yieldingly supporting saidcontact-pieces in such manner that their contact-faces when free areeach directed to be substantially parallel with the direction which theco-operating portion of the contact-face of the bar has at the moment ofcontact therewith.

7. In an electric switch, the combination of a row of contact-pieceshaving each a flat contact-face, a contact-bar having a contactfaceextending lengthwise of itself, means for guiding said contact-bar sothat one end thereof moves along a path extending in the direction ofthe line of said row of contactpieces, the other end thereof moves alonga path whose direction is transverse to that of the first end and itscont-actface is brought into contact in succession with the contactfacesof the contact-pieces, and means supporting said contact-pieces each soas to present its contact-face parallel to the co-operating portion ofthe contact-face of the bar at the moment of contact, and each capableof resiliently opposed pivotal movement and of resiliently opposedbodily displacement.

8. In an electric switch, the combination with a base, arow ofcontact-pieces having each a flat contact-face, means resilientlysupporting the contactpieces on said base, a contact-bar having acontact-face extending lengthwise along itself, and guiding meanscomprising a guide member having one end pivotally mounted on said baseand its other end pivotallv connected by a pin-and-inclined-slotconnection to one end of said bar,

7 contact faces of the contact pieces, which 7 contact-piecesarenormallysupported by the saic'l supporting means to have theircontactfaces each directed to. be substantially parand a. link that isivotally meuntediat one end On said base and has its other end piv--otally ccnneeted to the other end of said bar and movable along a pathWhose direction is transverse to that of the former endofther bar, saidguidlng means. bemg so arranged that the contact-face of the contact-baris broughtinto contact in succession with the

